Bobbin thread controlled signal for sewing machines



May 6, 1947. R. w. WINBERG 2,420,275

BOBBIN THREAD CONTROLLED SIGNAL FOR SEWING MACHINES Filed Aug. 24, 1943 C, p :2V/l

IN VEN TOR. 71. Mide/g Raynal' Patented May 6, 1947 air/0,275

BoBBIN THREAD ooNTRoLLED SIGNAL iron-SEWING MACHINES. f

Ragnar Winberg, York, N Y. Application August 24, 1943, Serial No. 499,759

This invention relates to new and useful improvements in a bobbin thread controlledsignal forsewing machines. i

More specifically, the invention proposes the construction of an automatic signal attachment" forfsewingmachines employing one' or more'nee'- dles and' alike'number of bobbins, one for each needle; and a stop signal for each of the bobbins in/f'a manner to indicate that'an approximateA predetermined amount ofthread still remains'onthebobbinwhen'thesignalis given. 'i

Th" objectof having a predetermined amount of thread to be left is important for these reasons;

f 1`." 'In' some. cases where the 'article -is Ismall "or where the .distanceto be stitched is'not too'greatv thefstitching' can continu'efuntil ithas 'reached` thenishingpoint; 'l l 2i Another advantage of having a predeterminiedamount ofcotton lefton the bobbin is that themachine' canbe stopped in leisureor enough'time^to prevent the machine from oontinuin'gthe stitching operation-without the bene lit of the bottom'o'r'bobbin thread." i

2`VSIStill anotheradvantagefis 'that the work will noti have to 'be pulled back'v to be 1re-stitched be-ry cause of the lack 'or thread on` the bobbin. This eliminates'waste 'timea lCertain fabrics and maf-'I terial's cannotl tolerate extra yneedle holes that the needle'punched after 'havingfthe workfpulledback' andrestitched. i i -f 14;' The operator will save time by not having to Vstop the machine to examine the amount of thread left'on the bobbins so asto avoid stitching without thread on the bobbins. I :iThe 'predetermined 'amountof thread to be left on the bobbinv after the signal is givenY can' b'eexplaind as follows: The amount "ofeturns of thread that' are `wound on the top side -off-thebob bin that remain on the bobbin'after the movableextendable member has been extended to close the signal circuit, 'can be usedlto finish stitching `to a iinishing point or tofstop' the machine inl ample time to replace'with-another fiullibobbin to avoid continuance of` the stitching operation` without the bottom or bobbin thread. Y.

Stillfurther thefinvention proposes mounting a movable member slidab-ly in the hollow-cylinclericalv hub of fa conventionally= constructed bobbin andV a. stationaryV contact f uponA a i portieriV of the sewingmachinev in amannertoclosean alarmI circuit when the movable memberengagesA the ixedcontact. '-'w 4- fs -f Another object of the invention proposes the provision of a resilient means tending to urge the movable .member -into anY extended .position from `1which will successively. be urged` the hub of the bobbin to engage the fixed contact and which maybe retained in an..inoperaeV tive position bythe thread wound upon thehubY of the bobbin so that when the .thread is nearly.. consumed. the movable member will beA released,

`to be urgedV into ,its operative position bythe.;

" alltimes-ina manner to-cause the. alarmcircuit.,

tobe continuouslyclosedi. v, .a vIt is -affurther object of this invention to oonstruct a bobbin thread controlled. Signal attach ment for a sewingl machine which issimpleand durable'and whichmay-be manufactured and sold.. atareasonablecost.1 i. For further comprehension of the invention, andV of the` objects andadvantages (thereof, rei.- erence .will be had. to .thefollowng descriptionand .accompanying drawings, andto .the appended, claimsin `which the variousnovel features oifthe; invention are more particularly set forth. l.-

In theaccompanyingdrawing forming a material part ofthis disclosure.- Fig. =1-isiaside.elevational View of a sewing machinehaving a bobbinthread controlled signal., attachmentI constructed. infaccordance` withvtl'iis` invention... H, Y-

=Fig. 271s an enlarged horizontal sectionalV view takenon theline2-.-2.oiIE?ig.1. .I i .l ,Figi 3 is airagmentarysectional view taken on the line 3-3 of.Fig. 2. i.

Fig. 4 is-a, vertical'sectional View perse. .Fig 5 is a horizontal sectional view taken on the-line 5-5 ofFigA.- i. i l Figi 6 is aview similar to Fig. 4 but illustrating the position of the parts when threadliswound. upon-thebobbin.v Y. Fig. 7 Yis awperspective view of the movable member used in this first form of the invention., Fig; -8 is. a schematic. wiring .diagram ofiY the device.v i. Fig-9 is an enlarged View similar toA a portion if the nebbia' of Fig. 3 bui illustrating a modification of the.

invention. .i i i i Fig. 10 is a perspective view of the movable member Used ,in ythe form of the invention'shown The signal attachment for sewing machine bobbins, according to this invention, is used in combination with a conventionally constructed sewing machine I9 having one or more reciprocating needles II. On the drawing, the sewing machine I Il is shown having two needles, but this is merely by Way of illustration. The machine I is further characterized by the fact that it has a bobbin case carrier I2, associated with a loop taker of any well known form, for each of the needles II, and each of the bobbin carriers I2 contains a spool-like bobbin I3. The bobbin case may be provided with any suitable latching means for retaining the bobbin therein, The bobbin carriers I2 are located in the bottom portion of the sewing machine I0, and over each of whichthere is a sliding plate I4. Reference numerals I indicate the openings for the needles II. The sewing machine functions in the usual manner in that the top loop of thread for forming the stitch normally passes around the bobbin carrier and bobbin during the sewing operation. Further details of the construction of the sewing machine Ill will not be given in this specification as they form no part oi this invention.

The spool-like bobbin I3 is characterized by a hollow cylindrical hub I5 and end anges I1 so that thread may be wound upon the hub between the end flanges. A movable member I8 is slidably mounted in one end of the hollow cylindrical hub I E of the bobbin I3. This movable member I 8 is of inverted cup-shape with its closed end forming a contact element I9 which normally projects from the face of its adjacent end iiange I'I. Oppositely disposed sides of the movable member I8 are formed with laterally extending projections 20. These projections, 29 engage complementary slots 2I formed in the sides of the hub I 6 of the bobbin for limiting movement of the movable member to the vertical and to prevent the movable member from becoming disengaged from the hub I6. The projections 29 serve a further useful purpose in holding the movable member in its retracted position shown in Fig. 6 as will become clear as this specification proceeds.

A stationary contact 22 is mounted upon the sewing machine I0, and more particularly upon the cover plate I4 above the longitudinal center of the hub I6 of the bobbin I3. A spring 23 is coaxially wound upon the hub I6 of the spool I3 and operates between the projected ends of the projections 2D and the adjacent end liange I1 of the bobbin I3 for urging the movable member I8 into an extended position from the end of the hub I6 in which its contact element I9 will contact the stationary Contact 22 as indicated by dot and dash lines I9' in Figs. 3 and 8.

In Fig. 8 a schematic wiring diagram of an alarm circuit 24 is shown. Each of the bobbins I3 has a similar alarm circuit 24. Each circuit 24, includes in series a source of power, the bobbin I3, the iixed contact 22 and a visual alarm 25 comprising an electric lamp mounted upon a portion of the sewing machine ID. With this construction when the contact element I9 engages the xed contact 22 the circuit will be cornpleted and the electric lamp 25 will be illuminated- The operation of as follows:

Thread 26 is wound upon each of the bobbins I3 with the movable members I8 held in a depressed condition. The thread 2li is wound over this form of the invention is and against the lateral projections 29 of the movable members I8 for holding the movable members I8 retracted against the action of the springs 23. The bobbins I3 are then returned to their bobbin carriers I2 and the cover plates I4 are closed bringing the xed contacts 22 into position over the movable members I8. The sewing machine is then operated in the usual manner and this continues until the thread 26 on one of the bobbins is used up to the point where it releases the movable member I8 to be urged outwards by its respective spring 23. The movable member I8 will then be extended causing the contact element I9 to engage the contact 22 closing the circuit 24 and illuminating its respective lamp 25. This will indicate to the operator of the machine that all of the thread on the bobbin I3 which controls that lamp has been nearly used. If the machine is not stopped immediately, for replenishing the supply of thread on the bobbin I3, the loops of rocating needle will continue to pass around the bobbin breaking the circuit causing the lamp 25 to flicker until the machine is stopped.

In the modification of the invention shown in Figs. 9 and 10, the construction of the signal attachment is similar to that previously described, except for the provision of means for preventing the lamp 25 from iiickering if the machine-is not stopped immediately after all the thread has been consumed on one of the bobbins I3.

This means comprises a pair of adjacent resiliently mounted contact elements 29 which project from the top of the movable member I8. Each of these contact elements 29 is mounted within an appropriate cavity formed in the movable member I8 and urged into an extended position by means of springs 30 also mounted within the cavities. These springs 30 possess merely enough tension to maintain the contact elements 29 in the extended positions illustrated in Fig. 9. With this construction, if the machine is not stopped immediately after the thread upon the bobbin has been used up, the loops of thread will pass around the bobbin I3 and successively pass between the contact elements 29 and the xed contact 22 so that one contact element 29 will be always engaging the ixed contact 22 preventing the circuit from being broken by the passing thread.

Means is provided for holding one oi the contact elements 29 in a retracted position against the action of its spring 30, permitting the circuit 24 to be broken if desired to have the lamp 25 flicker. This means comprises a lug 3I formed on one of the contact elements 29. This lug 3l engages a bayonet slot formed in the side of the movable member I8. The bayonet slot 32 has a long arm and an adjacent short arm. When the lug 3| is in position in the long arm, as shown in Figs. 9 and 10, the contact element 29 will be in an operative position. However, when the lug 3l is moved into the short arm of the bayonet slot 32 the contact element 29 will be in its inoperative retracted position within the movable member I8.

In other respects this form of the invention is similar to that previously shown and like reierence numerals identify like parts in each of the several views.

Wh'ile I have illustrated and described the preferred embodiments of my invention, it is to be understood that I do not limit myself to the precise constructions herein disclosed and the right is reserved to al1 changes and modifications thread formed by the recipclairnasenew and desire tclisecure byMUni'ted"V States LettersMPatent is :A

l. -In `adevice -ofthe-class described, a `spool like-bobbin for -insertion in thebobbin-- carrier of a sewing machine and having a hollow cylindrical hub and end iianges permitting th'reads to be wound on the hub, a movable extendable member slidably mounted in one end of said hollow cylindrical hub and having a contact element, a lateral projection from said extendable member passing through a slot in the side wall of said hub and over which said thread is to be wound for holding the extendable member retracted in said hub, resilient means operating between one end flange of said bobbin and said projection for urging said extendable member into an extended position in which said contact element will be extended from the face of the other` of said flanges when the thread is nearly completely unwound from said hub, and a stationary contact mounted on said sewing machine at a point adjacent said bobbin to be engaged by said contact element when in extended position for completing a circuit to signaling device.

2. In a device of the class described, a spool like bobbin for insertion in the bobbin carrier of a sewing machine and having a hollow cylindrical hub and end flanges permitting threads to be wound on the hub, a movable extendable member slidably mounted in one end of said hollow cylindrical hub and having a contact element, a lateral projection from said extendable member passing through a slot in the side wall of said hub and over which said thread is tobe wound for holding the extendable member retracted in said hub, resilient means operating between one end ilange of said bobbin and said projection for urging said extendable member into an extended position in which said contact element will be extended from the face of the other of said anges when the thread is nearly completely unwound from said h'ub, and a stationary contact mounted on said sewing machine at a point adjacent said bobbin to be engaged by said contact element when in extended position for completing a circuit to a signaling device, said movable member being of inverted cupshape and said contact element comprising the closed end thereof.

3. In a device of the class described, a spool like bobbin for insertion in the bobbin carrier of a sewing machine and having a hollow cylindrical hub and end flanges permitting threads to be Wound on the hub, a movable extendable member slidably mounted in one end of said hollow cylindrical hub and having a contact element, a lateral projection from said extendable member passing through a slot in the side wall of said hub and over which said thread is to be wound for holding the extendable member retracted in said hub, resilient means operating between one end ange of said bobbin and said projection for urging said extendable member into an extended position in which said contact element will be extended from the face of the other of said anges when the thread is nearly completely unwound from said hub, and a stationary contact mounted on said sewing machine at a point adjacent said bobbin to be engaged by said contact element when in extended position for completing a circuit to a signaling device, said resilient meanaomprisieeaeprinsoaxiallywane-upon..

said h'ub and operating bet J'eCtiQganld-adlagent. .ena-Han ge 4. In a device of the class described, a spool teral',

VVlike bobbin for insertionging,tlrebobbin carrier 0f. fin-Sewing. machineand .haring a hollow. Cylinf drical hub and end cangas permitmngtne thread to be wound on the hub, a movable"eXtendable member slidably mounted in one end of said hollow cylindrical hub and having a pair of adjacent resiliently mounted contact elements, a lateral projection from said extendable member passing through a slot in the side wall of said hub and over which' said thread is to be Wound for holding the extendable member retracted in said hub, resilient means operating between an end ange of said bobbin and said projection for urging said extendable member into an extended position in which said contact elements will be extended from the face of the other of said ilanges when the thread is nearly completely unwound from said hub, and a stationary contact mounted on said sewing machine at a point adjacent said bobbin to be engaged by said elements when in extended position to complete a circuit to a signaling device.

5. In a device of the class described, a spool like bobbin for insertion in the bobbin carrier of a sewing machine and having a hollow cylindrical hub and end anges permitting the thread to be wound on the hub, a movable extendable member slidably mounted in one end of said hollow cylindrical hub and having a pair of adjacent resiliently mounted contact elements, a lateral projection from said extendable member passing through a slot in the side wall of said hub and over which said thread is to be wound for holding the extendable member retracted in said hub, resilient means operating between an end flange of said bobbin and said projection for urging said extendable member into an extended position in which said contact elements will be extended from the face of the other of said anges when the thread is nearly completely unwound from said hub, and a stationary contact mounted on said sewing machine at a point adjacent said bobbin to be engaged by said elements when in extended position for completing a circuit to a signaling device, and means for holding one of said contact elements retracted.

6. In a device of the class described, a spool like bobbin for insertion in the bobbin carrier of a sewing machine and having a hollow cylindrical hub and end anges permitting the thread to be wound on the hub, a movable extendable member slidably mounted in one end of said hollow cylindrical hub and having a pair of adjacent resiliently mounted contact elements, a lateral projection from said extendable member passing through a slot in the side wall of said hub and over which said thread is to be wound for holding the extendable member retracted in said hub, resilient means operating between an end flange of said bobbin and said projection for engaging a complementary bayonet slot formed in said movable member. UNITED STATES PATENTS RA NBERG.

GNAR W WI Number Name Date REFERENCES CITED 5 1,703,897 Payne Mar. 5, 1929 1,455,387 Cobb May 15, 1923 The following references are of record in the 1436 460 Ringe Nov 21 1922 le of this patent: 

